The present invention relates to a new device for the injection of a slurry in the vicinity of the wall of a pile installed in the ground by driving, vibration, jetting, lowering into a drilled hole, or by any other appropriate means.
It is known that in some cases tubular piles installed in the ground to support, for example, petroleum-drilling rigs at sea, do not provide sufficient lateral friction, especially in carbonate soils. It is also known that it is then possible to increase this resistance by injecting under pressure a hardenable slurry, for example based on cement, in the vicinity of the walls of the tubular pile. This injection may be effected either outside the pile to increase the friction of the wall of the pile in relation to the soil, or in the interior of the pile in order to impart a rigidity to the soil there for the purpose of increasing the resistance of the pile to indentations.
The application of a method of this kind necessitates the installation along at least one of the generatrices of the pile of an injection tube composed of a steel tube of relatively small diameter which is connected at various points to injection valves which are located in or close to the wall of the pile and which permit the flow of the slurry when the pressure in the injection pipe is greater than that prevailing in the vicinity of the wall of the pile, without, however, allowing the slurry injected in this way to move in the opposite direction and return to the injection pipe.
In view of the fact that piles of this type may be several meters in diameter and that tens of meters of piles must be driven into the ground, it is desirable that the valves and the injection pipe should occupy the least possible space so as not to offer any noteworthy resistance to the driving.
It is also necessary for the attachment of the injection pipe to the wall of the tubular pile and the connections of it to the various valves to be perfectly resistant to the forces and vibrations which may be produced when the pile is installed.